1) Field of the Invention
The present invention relates to an ID (identification information or identification means) registration method for a tire pressure sensor, and further to an ID registration apparatus for implementing this method, an ID registration tool for a tire pressure monitoring system, a tire with an air pressure sensor, and a tire pressure monitoring apparatus.
2) Description of the Related Art
So far, as a tire pressure monitoring system, there has been known a system disclosed in Japanese Patent No. 3212311.
In such a type of conventional tire pressure monitoring system, an air pressure sensor with a transmitter is mounted on each tire, and an air pressure detection signal, together with the corresponding sensor ID, is transmitted from the air pressure sensor to be received by a tire pressure monitoring apparatus mounted on a vehicle body side so that, when there is, at least, a tire unusual in air pressure, an indication appears on an indicator to issue an alarm.
In this system, the ID for each sensor is also registered (put) in the tire pressure monitoring apparatus, and checking this ID, a decision can be made as to whether or not the received detection signal belongs to an air pressure sensor of a tire of his/her own vehicle.
In a conventional system, this sensor ID is allocated to each sensor by a sensor maker at the stage of shipping, while in a car maker, a tire pressure monitoring apparatus of a vehicle body is set to an ID registration mode in assembling a vehicle to receive an ID transmitted from each sensor for registering it in the tire pressure monitoring apparatus.
More concretely, as shown in a block diagram of FIG. 78, a conventional tire pressure monitoring system is made up of air pressure sensors 110, 120, 130 and 140 mounted on the corresponding tires and a tire pressure monitoring apparatus 150 mounted on a vehicle body. The air pressure sensor 110 includes a pressure sensor 111 for detecting an air pressure in a tire, an ID memory 112 for storing a sensor ID in advance, and a transmitting circuit 113, a power supply battery 114, a control unit 115 and a transmitting antenna 116. The other air pressure sensors 120, 130 and 140 have the same configuration.
The tire pressure monitoring apparatus 150 includes a receiving circuit 151, a receiving antenna 152, a power supply circuit 153, a control unit 154, a memory 155 and a communication circuit 156 for transmitting indication data to an indicating device 160 such as an indicator or an LED. Moreover, the power supply to this tire pressure monitoring apparatus 150 is from a vehicle-mounted battery 170, and as various types of switches, in particular, to the control unit 154, there is connected a mode switch 180 made to carry out the switching between a normal operating mode and an ID registration mode.
The ID registration in a vehicle manufacturing line is conducted in accordance with a procedure shown in a flow chart of FIG. 79. That is, the control unit 154 registers a sensor ID included in a received signal in the memory 155 when the receive signal level satisfies a predetermined condition (decision level) (P7140, P7150). In this way, in the conventional system, the ID of an air pressure sensor actually mounted on each tire of a vehicle is registered in the monitoring apparatus side, and a decision is made as to whether an ID included in a signal received through the receiving antenna 152 agrees with an ID registered in the memory 155 and, if it agrees therewith, a decision is made on a tire pressure state on the basis of a pressure signal received together with that ID and an indication apparatus on the indicating device 160 on the basis of the decision result. In this case, the ID registration is for preventing an indication from being made in error on the basis of a signal from an air pressure sensor of a tire of a vehicle running nearby.
However, in a vehicle assembling process, since an air pressure sensor ID registration work is done in a state where many vehicles flows on the line, a radio interference problem arises in which one vehicle receives an ID signal from an air pressure sensor of other vehicles to conduct mistaken registration. This problem also applies to a case in which a sensor ID is re-registered in a repair shop or the like.